1. Field of the Invention
The present invention relates generally to the field of antifriction bearings and housings for such bearings. More particularly, the invention relates to a sealing system for a bearing assembly including features advantageous in certain applications, such as in the food and beverage industries.
2. Description of the Related Art
A wide range of applications exist for antifriction bearings, such as ball bearings, roller bearings, needle bearings and the like. In many industrial and material handling systems, such bearings perform a fundamental function of permitting rotating machine elements to turn with little resistance and thereby to effectively transmit power and motion between drive system components. Applications for such bearings include conveyors, mixers, pump drives, and the like, to mention just a few.
In general, bearings of the type commonly used in most industries include an inner race, an outer race, and a plurality of antifriction bearing elements disposed therebetween. The bearing elements are captured by the races and permit the races to rotate freely with respect to one another. The bearing assembly is typically installed in and supported by a housing. A number of housing types are known and are in common usage, including pillow block styles, two and four bolt flanged styles, take-up frame styles, and so forth. In addition to supporting the bearing inserts, such housings include features that permit them to be easily attached to machine frames and other support structures at the application. Depending upon the housing style, these features typically include support feet or flanges traversed by apertures for receiving fasteners. Once mounted on the machine frame, a base surface of the bearing housing generally abuts the machine frame and forms a solid foundation for both the bearing insert and for the machine elements held in rotation by the bearing insert.
Housings of the type described above are commonly made of a variety of materials depending upon the particular application, the loads to which the bearing insert will be subjected and the environmental conditions of the application. For example, in most bearing styles, metal housings provide sufficient mechanical support and resistance to loads. However, such metal housings are not well-suited to certain applications. Specifically, in certain industries health or environmental constraints may make the use of metal bearing housings difficult or impossible. In the food and beverage industries, conditions tend to promote the growth of fungi, molds, bacteria and other microorganisms. Health requirements often necessitate frequent washing of processing and material handling equipment including bearings and their housings. Under such conditions, the bearings within conventional bearing housings may tend to corrode or otherwise degrade in ways that would contaminate the working conditions of the machinery and/or the product processed by the machinery. Similarly, in chemical processing industries and certain marine applications the presence of corrosive substances may significantly reduce the life of conventional metal bearing housings.
There is a need, therefore, for an improved bearing assembly which can be used in applications where environmental or health conditions require superior resistance to the proliferation of microorganisms. More particularly, there is a need for a bearing assembly that will prevent contaminants, such as microorganisms, from proliferating on or within a bearing assembly.